The present invention relates generally to the field of electrochemical systems. More particularly, the present invention relates to dual mode electrochemical systems that can produce hydrogen in a form of hydride and electrical energy.
Fuel cell technology has the potential to significantly reduce harmful emissions. Fuel cells are capable of efficient energy conversion and can be used in a variety of applications including transportation applications, portable power sources, home and commercial power generation, large power generation and any other applications that would benefit from the use of such a system. With respect to transportation applications, fuel cells represent a promising alternative to vehicles with conventional internal combustion engines, which engines burn fossil fuels such as gasoline or diesel. Internal combustion engines produce harmful particulates and add greenhouse gases to the atmosphere. Fuel cell vehicles, on the other hand, may be fueled with pure hydrogen and emit only water and energy in the form of electric power and heat. In fact, fuel cell vehicles may be twice as efficient as conventional vehicles.
Typically, fuel cells create energy through a chemical process that converts hydrogen fuel and oxygen into water, producing electricity and heat in the process. Fuel cells operate very much like a battery with constantly renewed reactants. While batteries are recharged using electricity, fuels cells are recharged using hydrogen and oxygen. A fuel cell stack uses the hydrogen supplied by the fuel source to produce electricity to power any device including one or more electric motors, which motors move a vehicle. A fuel cell stack may consist of hundreds of individual fuel cells. In many cases, a battery is used to store electricity produced by the fuel cell stack and by other systems in the vehicle, such as regenerative braking systems. The energy stored in the battery may also be used to power the electric motors as well as additional electrical systems in the vehicle.
Unlike a battery that is limited to the stored energy it holds, a fuel cell is capable of generating energy as long as fuel is supplied. While battery electric vehicles use electricity from an external source stored in the battery, fuel cell vehicles create their own electricity. Fuel cells are also capable of providing a greater energy density or current density than conventional batteries for electric vehicles, allowing larger amounts of energy to be produced continuously. This may allow fuel cell vehicles to be equipped with more sophisticated and powerful electronic systems than those found in current gasoline powered vehicles. For example, an increase in the number of control sensors in a vehicle may improve handling and braking systems, making vehicles safer.
Hydrogen used in cells as a fuel may be produced from a fossil fuel such as natural gas, methanol etc. through a reforming process. The hydrogen produced by the reforming process is not pure, lowering the efficiency of the fuel cell. Adding a reformer to convert hydrocarbon fuel into hydrogen drops the overall efficiency of the fuel cell to about 30 to 40 percent.
Therefore there exists a need in the art to find effective and efficient ways to constantly produce and store hydrogen in a fuel cell in order to provide continuous operation. Still further, what is needed is a rechargeable fuel cell system that derives energy from an internal source and stores it within the system.